A unique center for near-infrared imaging is being constructed around the tunable KNbO3 laser system requested in this proposal. The equipment will be employed in the collection of data for several multidisciplinary projects aimed at improving human health through the state-of-the-art near-IR/supercomputer techniques. These multidisciplinary projects (funded by 12 active PHS grants), currently in progress at U.K., involve a total of 7 new and tenured faculty, and their students, on the Medical Center and Lexington campuses; the Center for Computational Sciences, the Kentucky Heart Institute, and the Sanders-Brown Center on Aging. Each of the projects involves the use of near-infrared spectrometry to image noninvasively chemical and structural changes associated with disease. The projects are based in three broad components: l. The Stroke Program, which will employ the equipment in the imaging of human volunteers and miniature swine used as an animal model of atherosclerosis. The laser will be used as a bright, tunable light source to obtain transcutaneous 3-D spatial resolution of plaques, with chemical composition profiles collected at various stages in lesion development. These data will be correlated with results from duplex ultrasound and lipoprotein electrophoresis from Stroke Program projects. 2. The in vivo chemical analysis and high-resolution imaging of the structure of atherosclerotic plaques using a near-IR fiber- optic catheter. New imaging algorithms for massively parallel supercomputers and intraarterial fiber-optic cameras are the most recent technological discoveries in this project. The intraarterial fiber-optic techniques used at other institutions cannot provide chemical determinations of constituents, such as HDL, LDL and apolipoproteins. The nondestructive chemical analysis of single lesions over time virtually guarantees a new understanding of the mechanisms of lesion formation and growth. 3. The analysis of brain damage resulting from stroke and/or head injury. Most methods for identifying and quantifying lipids and proteins are separation methods and require the removal of tissue. The inability to use separation techniques in vivo limits observation of the direct effect of drugs on ischemia- related brain damage. Near-IR imaging allows in vivo drug testing in real time.